If you are using your own personal device: In MS Word: go to Tools > Templates and Add-ins > place a tick next next to any of the EndNote item(s) > press OK.
In EndNote Desktop: go to EndNote 20 > Customizer > place a tick next to the Cite While You Write option > press Next > press Next.
If the 'EndNote 20' tab is missing from MS Word's toolbar, it is because:
In MS Word, the 'EndNote 20' tab should appear at the top of the page within the toolbar.
